In general, the present invention relates to a multichannel broadcasting system. More particularly, the present invention relates to a broadcasting system wherein system reliability is improved by providing a backup output buffer apparatus to a plurality of output buffer apparatuses each provided for some output channels.
In recent years, much attention is paid to multichannel broadcasting using a satellite or communication cables. The multichannel broadcasting is different from single channel broadcasting using the ordinary and traditional ground wave in that, in the case of the former, one broadcasting station broadcasts different programs to a number of channels. Thus, in a broadcasting station, it is necessary to transmit a program along with advertisements inserted into the program, commercials and an advertisement for the program to each channel. It should be noted that a commercial is referred to hereafter simply as a CM.
In general, a program requires a long transmission time while a CM or a program advertisement has a short period in the range 15 to 30 seconds. However, there are a number of CM or advertisement types. Moreover, the same CMs and advertisements are broadcasted repeatedly from time to time.
For the above reason, in an ordinary broadcasting system, short broadcast contents such as CMs are entered temporarily in a storage apparatus to be transmitted later at appropriate times in accordance with a play list created separately for transmission use. Prepared for each channel, a play list is a list of broadcast contents to be output to the channel. A play list which differs from channel to channel is used for transmitting CMs and other short broadcast contents for the respective channel.
However, transmission of short CMs and other short broadcast contents of many types to a number of channels accompanying the migration to multichannel broadcasting entails extremely complicated work. As a solution to this problem, there has been proposed a broadcasting system wherein an output buffer apparatus is provided for each channel or each group of channels for storing data of broadcast contents such as CMs to be transmitted to the channel or the channels in the group. The data stored in the output buffer apparatus is signals such as images, sound and characters. By providing a plurality of output buffer apparatuses, the work to transmit broadcast contents to a plurality of channels can be made simpler.
When a failure occurs in an output buffer apparatus, however, the transmission of CMs and other broadcast contents is suspended till the apparatus gets fixed. It is thus necessary to provide a backup output buffer apparatus. Since the multichannel broadcasting system itself is still at a stage of development, nevertheless, a useful proposal as to how a backup output buffer apparatus should be configured has not been made yet.
It is thus an object of the present invention to provide a multichannel broadcasting system having a low cost backup output buffer apparatus capable of properly coping with a failure occurring in an output buffer apparatus.
It is another object of the present invention to provide a multichannel broadcasting system having a simply configured and highly reliable backup output buffer apparatus capable of properly coping with a failure occurring in an output buffer apparatus.
In order to solve the problems described above, the present invention provides a multichannel broadcasting system for transmitting signals representing broadcast contents to a plurality of output channels. The multichannel broadcasting system comprises:
(1) a broadcast content storage apparatus for storing a plurality of broadcast content signals;
(2) a plurality of main output buffer apparatuses each provided for some of the output channels wherein signals representing broadcast contents to be transmitted to the associated output channels are copied from the broadcast content storage apparatus thereto for transmission at transmission times; and
(3) a plurality of backup output buffer apparatuses fewer in number than the main output buffer apparatuses wherein signals representing broadcast contents to be transmitted to all the output channels are copied from the broadcast content storage apparatus thereto.
When one of the main output buffer apparatuses employed in the multichannel broadcasting system provided by the present invention is out of order, signals representing broadcast contents for output channels associated with the broken apparatus are transmitted to the output channels from the backup output buffer apparatus.
According to the present invention, a plurality of backup output buffer apparatuses fewer in number than the main output buffer apparatuses each capable of storing copies of signals representing broadcast contents for more output channels than the output channels associated with one main output buffer apparatuses. Thus, in the event of a failure occurring in any of the main output buffer apparatuses, the transmission of a signal representing broadcast contents can be continued by transmitting the signal from a backup output buffer apparatus without suspension of the broadcasting through the use of few hardware resources.